A year ago I set off on a journey to create a custom board that would be designed to run SamplerBox - the best open-source sampler available.
And the great news are, this is now done. I've designed and manufactured a board that connects to Raspberry Pi and provides necessary audio interfaces: MIDI IN/THRU, onboard DAC, balanced line outputs, headphone amp, display and control buttons.
It is optimised to have all necessary connections onboard and yet be portable. Onboard DAC uses same chipset as best Raspberry Pi sound cards available on the market do and the sound quality is terrific. This sampler is not becoming a bottleneck in quality of your setup. Sounds as good as your samples and listening devices are.
At this point I need to ask for your help. To guide development of this project further, I'd like to ask you whether you would be interested to use this device. Would you like to get the schematics to make a DIY project? Or an assembled board to make DIY easier and faster? Or you'd rather be interested in owning a pre-made sampler instead? Let me know!
P.S. The HD44780 issue from the previous post: turned out a faulty microUSB cable not handling current well and causing 5V voltage rail to drop below 4.3v. (Instantaneously, but was enough to disrupt display updates.)